Your headphone selection will probably depend on what type you music you usually listen to. For classical and jazz I think the AKG K701/K702 is pretty hard to beat. They are known for their huge soundstage and great clarity. If you are more into rock than the Denon D5000's would be a great option. Many people have two sets of headphones (the above would cost less than a grand). Beyerdynamic DT880's are popular all-rounders along with the Sennheiser HD600/HD650's.
The woo-audio amps are great (take a look at the WA6SE) and so are the headamp, audio-gd (Phoenix or Rox), ray samuels, and headroom offerings. There are so many choices out there and the best option really depends on your headphones and personal preferences. I'd head over to headfi.org and go browse around their forums. You should be able to create an amazing sounding headphone setup for under $2500 along with your PS Audio DLIII.
The woo-audio amps are great (take a look at the WA6SE) and so are the headamp, audio-gd (Phoenix or Rox), ray samuels, and headroom offerings. There are so many choices out there and the best option really depends on your headphones and personal preferences. I'd head over to headfi.org and go browse around their forums. You should be able to create an amazing sounding headphone setup for under $2500 along with your PS Audio DLIII.